Better processor or bettet center channel speaker

I am currently upgrading my hometheater system. Since i have limited budget, is it better to purchase better center channel speaker first or purchase better processor. Please give feedback as to which option provides biggest bang for a buck.

That depends on the rest of your system. List your current components here so we can be of more help.
My center channel is B&W matrix HTM and my surround processor is Rotel RTC-965. I welcome any suggestions.
Are you kidding me ? The BW Matrix HTM is a fabulous center channel. It is in a totally different league than your Rotel. Get a better processor !!
That surround processor if not up to the HTM but it is still a decent one. If you do not like the sound, then maybe you need to look at your amp.